1. Field of the Invention
The present invention relates to a gyroscope sensor circuit applicable to mobile terminals such as cameras, cell phones, or the like, and more particularly, to a gyroscope sensor circuit capable of maintaining constant amplitude in a driving signal of a gyroscope sensor, decreasing the influence of temperature, and reducing settling time, by using automatic gain control.
2. Description of the Related Art
In general, a gyroscope sensor (i.e. a gyroscope) may measure an angular velocity Ωz with Coriolis Force (Fy=ΩmzVx) in the state in which a mass body having a certain level of mass m is vibrated at a constant velocity Vx. Here, a velocity Vx should be constant at all times, in order to precisely measure an angular velocity Ωz.
In general, the gyroscope sensor performs self-oscillation by using a feedback circuit. At this time, a velocity Vx is determined according to the resonant frequency of self-oscillation and feedback gain.
However, when the velocity Vx is affected by the temperature characteristics of amass body, errors in measuring acceleration may occur.
Moreover, in order to enhance the sensitivity of the gyroscope sensor, a mass body having a high Q-factor is used. In the case that the Q-factor is high, the settling time of the self-oscillation of the sensor may be extended.